A load balancer is a server set that includes multiple servers arranged in a symmetric manner. All the servers have equal standing, and each server may independently provide service externally without assistance from other servers. Through load sharing, requests received from the outside are equally allocated to servers in the symmetric structure, and a server that receives a request independently responds to the originator of the request. In load balancing, the requests of the client can be equally allocated to a server array, so that important data is rapidly obtained, and a problem of a large amount of concurrent access is avoided. In this kind of clustering technology, performance that approximates to that of a mainframe can be achieved with the least amount of investment.
With the development of cloud computing technology, various services are migrated to a cloud environment, and cloudification requirements are also imposed on load balancers. In response, a virtual load balancer (vLB) is developed.
Currently, most virtual load balancers are virtualized and software-defined conventional load balancers. This cannot meet requirements of cloud computing for high reliability, horizontal extension, and high bandwidth on the vLB. To improve vLB service reliability, services are usually provided by using two vLBs in a primary-secondary relationship. Heartbeat information is transferred between the primary vLB and the secondary vLB by using the Virtual Router Redundancy Protocol (VRRP). When the secondary vLB finds that the primary vLB is down, the secondary vLB continues working in succession to the primary vLB. In the primary-secondary relationship implemented by using the VRRP, after the primary vLB is down, the secondary vLB continues working. The active/standby switchover needs an amount of time, and this causes traffic interruption in the switchover process. In addition, one load balancing node needs to perform load balancing on all load balancing services. When load balancing access traffic is large, bandwidth of the centralized load balancing node becomes a bottleneck, and service congestion and delays are caused.